In 2018, Hopyard Lumber changed its inventory method from LIFO to FIFO. Inventory at the end of 2017 of $120,000 would have been $135,000 if FIFO had been used. Inventory at the end of 2018 is $153,000 using the new FIFO method but would have been $139,000 if the company had continued to use LIFO.

What is the effect of the change on 2018 cost of goods sold?